Department of Chemistry

Abstract:

Victor S.-Y. Lin
Department of Chemistry
U.S. DOE Ames Laboratory
Iowa State University
Ames, Iowa 50011-3111
U.S.A.
E-mail: vsylin@iastate.edu
Telephone: +1-515-294-3135

We have recently synthesized a series of multi-functionalized, MCM-41 type mesoporous silica nanosphere (MSN) materials.1-8 The mesopore surface of these materials was derivatized with fluorescence sensor groups that could recognize and react with amino acid-based neurotransmitters.1,5 The exterior surface of the MSN materials was covalently coated with polylactides or polypeptides.5 By utilizing the polymer layer as a gatekeeper to regulate the rates of diffusion of several structurally similar neurotransmitters, such as dopamine, tyrosine, and glutamic acid, into the sensor mesopores, a highly selective fluorescence biosensor that could distinguish dopamine from glutamic acid under physiological condition was synthesized. In addition, the utilization of these gatekeeper-functionalized MSN materials as selective catalysts will be demonstrated.2,4,7

These MSN materials were also designed as a stimuli-responsive controlled release delivery system.3,6,8 Several pharmaceutical drugs and neurotransmitters were encapsulated inside the mesopores of MSN by capping the openings of the mesopores with various chemically removable caps, such as surface-derivatized cadmium sulfide (CdS) nanocrystals,3 superparamagnetic iron oxide nanoparticles,8 and cell membrane permeable dendrimers, e.g. polyamidoamine (PAMAM) dendrimer,6 to block the molecules of interest from leaching out. We studied the stimuli-responsive release profiles of several drug/neurotransmitter-loaded MSN systems by using various non-cytotoxic chemicals as release triggers. Furthermore, the gene transfection efficacy, uptake mechanism, and biocompatibility of the capped-MSN system with various cell types, such as neural glia (astrocytes), human cervical cancer (HeLa), and Chinese hamster ovarian (CHO) cells were investigated.6 The mesoporous structure of the MSN material allows membrane impermeable molecules, such as pharmaceutical drugs and fluorescent dyes, to be encapsulated inside the MSN channels. The system renders the possibility to serve as a universal transmembrane carrier for intracellular drug delivery and imaging applications.

1. Lin, V. S.-Y.;* Lai, C.-Y.; Huang, J.; Song, S.-A.; Xu, S. J. Am. Chem. Soc., 2001, 123, 11510.
2. Lin, V.S.-Y.;* Radu, D. R.; Han, M.-K.; Deng, W. Kuroki, S.; Shanks, B. H. Pruski, M. J. Am. Chem. Soc., 2002, 124, 9040.
3. Lai, C.-Y.; Trewyn, B. G.; Jeftinija, D. M.; Jeftinija, K.; Xu, S.; Jeftinija, S.; Lin, V. S.-Y.* J. Am. Chem. Soc., 2003, 125, 4451.
4. Huh, S.; Chen, H.-T.; Wiench, J. W.; Pruski, M.; Lin, V. S.-Y.* J. Am. Chem. Soc. 2004, 126, 1010.
5. Radu, D. R.; Lai, C.-Y.; Wiench, J. W.; Pruski, M.; Lin, V. S.-Y.* J. Am. Chem. Soc. 2004, 126, 1640.>br> 6. Radu, D. R.; Lai, C.-Y.; Jeftinija, K.; Rowe, E. W.; Jeftinija, S.; Lin, V. S.-Y.* J. Am. Chem. Soc., 2004, 126, 13216.
7. Huh, S.; Chen, H.T.; Wiench, J.W.; Pruski, M.; Lin, V.S.-Y.* Angew. Chem. Int. Ed. 2005, 44, 1826.
8. Giri, S.; Trewyn, B.G.; Stellmaker, M.P.; Lin, V.S.-Y.* Angew. Chem. Int. Ed. 2005, 44, 5038.

Host: Jie Liu

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